In the Department of Otolaryngology at the Johns Hopkins Hospital, clinical investigations are carried out on patients with cochlear and vestibular dysfunctions and a variety of pathological conditions involving the different structures of the temporal bone. These investigations include an oto-neurological examination, cochlear and vestibular function studies, roentgenological investigations, and when indicated, additional diagnostic studies. The roentgenological, medical, neurological and neurosurgical examinations are performed by the respective services. At autopsy the temporal bones are removed. These temporal bones are subsequently prepared for microscopic examination in the Temporal Bone Pathology Laboratory located in the Traylor Research Building of the Johns Hopkins University School of Medicine. The objectives of this research are to correlate clinical and histopathological observations and thereby to increase knowledge about the poorly understood mechanisms of certain disease processes involving the cochlea and vestibular labyrinth and other structures of the human temporal bone. The selective collection of temporal bones from patients with diseases involving the ear, who have been carefully studied, represents a valuable approach which obviously will continue to add significant information to a better understanding of the nature and the sequence of events in the development of impairment of hearing and dysfunction of equilibrium. Once the pathogenesis is better understood, prevention of a disease process becomes a possibility.